just redid my motors and dynoed them . They made 642hp at 5300 and 720ftlbs. I am a little unhappy with the hp # what can I expect for speeds. motors are 588 talldecks. I was hoping to get to 90mph but Idk. the torque is all there and then some but will that lower hp do the job? boat is a 98 stepped fever with -2 shorties side by side. last year with the 540 talldecks spun 30p5xs to about 5000 and ran 84gps what do u guys with think??

Need more info. Show or post dyno #'s. Need to see #'s thru all rpms tested.

What cam, cid, heads, compression ?

I think you should be close, what rpm was your peak torque

What did the 540s make? You'll probably be in the upper 80s. 90 will be a stretch with only 640 a side.

My 38 Fever took 720hp a side to run 92mph, Re degree the cams ,turn the RPM'S UP & let her eat . The boat could run low 90's with 588 inch motors easy!

I would guess the 540s with a reasonable build would make 620-650 hp.

Peak torque was at 4500 I will get the sheets today

Racn fever how much torque did u have with that 725 hp I guess I tryn to find out if I need to go back in and change cams intakes and carbs to dominators. U think my big torque # will carry this boat

Need cam specs , intake & carb info, cyl head info, & header type . Looking at your dyno # you may not have enough cam to make HP in the higher RPMs, Somethime Engine Builders are not able to run the big cams to make power in large CID motors due to inadequate exhaust headers.Best to keep CID around 540 unless you have $$$ for BIG TUBE HEADERS.

TQ peak at 4500 and HP peak at 5300 rpm ?

Somethings off big time. Peak hp is typically 1200-1400 rpm higher than peak tq.

Still haven't answered parts used. Will be helpful to see if it;s a problem there or in tuning/rigging.

Got dyno sheets so we can see fuel flow #'s, intake cfm, A/F ratio's, etc,etc ?